Enclosed switch with cover-carried operator and interlock mechanism

ABSTRACT

An enclosed switch, of the type wherein the switch-operating handle is mounted on a hinged cover of a box, has snap action actuating mechanism and interlocking mechanism which are also mounted on the cover, the snap action mechanism being operably connected with the switch-operating mechanism at all times so that the contacts can be disengaged while the cover is open and the cover can be closed while the contacts are either engaged or disengaged; but, the switch contacts can not be moved into engagement while the cover is open without disabling the interlock. A turnable handle operates snap action means having an actuated element operating transversely of the enclosure to actuate the operating mechanism and switch contacts which move in different planes at right angles thereto in the enclosure.

United States Patent 2,216,298 10/1940 Rowe lnventor Paul M. Christensen West Orange, NJ.

Appl. No. 848,948

Filed Aug. 11, 1969 Patented May 25, 1971 Assignee Arrow-Hart, Inc.

Hartford, Conn.

ENCLOSED SWITCH WITH COVER-CARRIED OPERATOR AND INTERLOCK MECHANISM ZOO/50.1

2,256,910 9/1941 Rowe 3,197,582 7/1965 Norden Primary Examiner-Robert S. Macon Assistant Examiner-M. Ginsburg Attorney-Davis, Hoxie, Faithful] & Hapgood ABSTRACT: An enclosed switch, of the type wherein the switch-operating handle is mounted on a hinged cover of a box, has snap action actuating mechanism and interlocking mechanism which are also mounted on the cover, the snap action mechanism being operably connected with the switchoperating mechanism at all times so that the contacts can be disengaged while the cover is open and the cover can be closed while the contacts are either engaged or disengaged; but, the switch contacts can not be moved into engagement while the cover is open without disabling the interlock.

A tumable handle operates snap action means having an actuated element operating transversely of the enclosure to actuate the operating mechanism and switch contacts which move in different planes at right angles thereto in the enclosure.

ZOO/50.1 ZOO/50.1

PATENIED NAYZSIHTI sum 1 M 4 //7 van for Pou/ M. Chns/ensen By Dav/sflonfa/lh/u/l 8 Hapgood fol Alforneys PATENTED HAYES ml SHEET 2 OF 4 mm {5%, m? fl /HG 8.5 n 5 nmm 5 4 0 a 4 WM Z PH m 2 0 4 m w This invention relates to fused electric switches which are housed in a box having a hinged cover to provide access to the switch contacts, mechanism nd fuses. More particularly, the invention relates to an improved interlocking mechanism to prevent opening of the cover while the switch contacts are engaged.

One object of the invention is to provide improved snap action means for electric switches useful generally and in particular in an enclosed switch when mounted on a hinged cover.

Another object is to provide an interlocked cover and switch of the aforesaid type in which the operating means and interlocking mechanism are at all times operatively connected, whether the cover of the enclosure is open or closed. A related object is to provide means normally preventing movement of the switch contacts into engagement while the cover is open but permitting the contacts to be disengaged while the cover is open and permitting closure of the cover the contacts are in engaged or disengaged.

Other objects and advantages of the invention will appear as the invention is described in connection with the accompanying drawings.

In the drawings:

FIG. 1 is a side elevation view partly in section and partly broken away, of a structure embodying the invention.

FIG. 2 is an exploded perspective view of certain parts of the contact operating mechanism.

FIG. 3 is a side elevation view of the operating mechanism unit showing particularly the latch member.

FIG. 4 is a section view through the operating mechanism with the top side plate removed and showing the parts in on" position.

FIG. 5 is a view similar to FIG. 4 but with the parts in off position.

FIGS. 6 and 7 are perspective views of the latch member and the connecting bar respectively of the actuating mechanism.

FIG. 8 is a plan view of the actuating mechanism unit removed from the cover in off",position, showing the relation of the handle and the side of the box.

According to the invention an enclosed switch, of the type wherein the switch-operating handle is mounted on a hinged cover of a box, has snap action actuating mechanism and interlocking mechanism which are also mounted on the cover and the snap action mechanism is operably connected with the switch-operating mechanism at all times so that the contacts can be disengaged while the cover is open and the cover can be closed while the contacts are either engaged or disengaged but the switch contacts can not be moved into engagement while the cover is open without disabling the interlock.

Referring to the drawings, a rectangular enclosure or box 10 has a hinged cover 12 which carries a switch-operating handle 14 and switch-operating and interlocking mechanism designated generally by the numeral 40. Inside the box 10 is mounted a base member 16 of insulation on which is mounted a plurality of sets of fixed contact members 17, 17 the sets being mounted side by side in any desired number depending on the number of lines or poles to be controlled by the switch. Conventional fuse terminals 18 connected with one contact 17 of each set are provided for cartridge type bus fuses.

Movable bridging contact members 19 of U-shape or of any desired or conventional form are mounted in rectangular insulating blocks 20 that slide rectilinearly in cavities in the base 10 to and away from the bottom or backwall of the box as the switch is operated to cause engagement and disengagement of the fixed contacts 17, 17' sets by the bridging contacts 19. Preferably, the fixed contacts are of blade type and the movable contacts are a clip or jaw type mounted in any desired way in the insulating blocks 20.

For moving the movable contacts a U-shaped bail 22 is pivotally mounted in the opposite sidewalls of the box by coaxial pivot pins 21. One arm 22a of the bail is extended beyond its pivot pin toward the opposite end of the box into engagement with the forked end of a bellcrank lever 23 (see FIG. 2) that extends in a plane normal to the axis of the bail arm extension 22a so that as the crank pivots, it moves the bail about its pivots 21. The transverse portion 221 of the bail engages in parallel aligned slots in each of two flat metal plates 24 (only one is visible, in FIG. 1) secured by screwbolts against opposite parallel sides of the movable-contact-carrying insulating blocks 20, the slots being stamped or cut into the plates 24 in a direction parallel to the back or bottom wall of the box.

For operating the bellcrank lever 23, a flat rectilinearly slidable bar 25 (FIGS. 1 and 2) is mounted on the top face of a U-shaped bracket or strut 26 which extends across the top of the box 10 and is afiixed by its parallel legs 26a to the inside surfaces of the opposite walls of the box. For mounting the slide bar 25 movably on the bracket, two spaced aligned slots 26: are formed in the transverse portion of the strut 26 to receive loosely screwbolts 25s or other protuberances from the bar 25 which can hold the slide bar on the strut and also guide it in rectilinear movement over the top surface of the strut. The strut also supports the bellcrank lever 23 pivotally by means of a flange 26f bentdown from one edge of the strut normal to the plane of the strut. A pivot pin passes through the flange 26f through a hole 230 of a bellcrank lever. The bellcrank lever arm 23b is bent midway along its length so that its end is offset and can extend through an aperture 260 in the flange and upwardly through a recess 26d in the side of the strut to engage a recess 25r win the side of the slide bar 25. Preferably, the edges of the metal at the ends of that recess are bent up to provide bearing surfaces 25c for the end 23b of the bellcrank lever. The slide bar 25 is operated by a connection from the actuating mechanism 40 will now be described.

The actuating mechanism is a unit that is mounted on the underside of the cover and is operated by a pivoted handle 14 that is mounted on the top side of the cover. The unit is generally rectangular having parallel metal cover and bottom plates 41 and 42 and a sideplate 43, and parallel end plates 45 and 46, the terms top, bottom, side and end being used in relative sense and not as limitations on the invention ,or its use.

The actuating mechanism has a laterally slidable assembly designated generally by the numeral 30 (FIGS. 1, 3 and 8) consisting of two bent sheet metal actuating bars 32 and 34 extending across the opposite faces of the actuating mechanism unit 40, bar 32 being between the unit and the box cover 12. These bars have corresponding ends extending beyond the unit, bent in overlapping relation into parallel concentric arcs whose center is the pivot of the hinge 13 of the cover 12. The bar 34 has its midportion 34c first bent up along side of the end plate 46 of the unit 40 and its end 340 bent arcuately parallel to the end 320 of the bar 32. Between the arcuate ends 320, 34a is mounted slidably a narrow slidable L-shaped arcuate sheet metal tongue 36 having a longitudinal slot in its arcuate leg part through which extends two spaced rivets 33 which connect and extend through the arcuate ends 32a, 34a of the late rally movable actuating bars 32, 34. The width of the tongue 36 and bars 32, 3,4 are preferably equal. The bar ends 32a, 34a extend between the bearing edges or lugs 25b of the slide bar 25 so that as the actuating bar assembly 30 moves laterally it carries with it the slide bar 25 and hence operates the contact mechanism described above.

Tongue 36 and arcuate ends 32a and 34a are positioned between the bearing lugs 25b of the slide bar 25 (FIGS. 1 and 2) but when the cover is fully opened the ends 320 and 34a are carried out of the area between the lugs 25b. However, the lateral extension 36x of the tongue catches beneath the slide bar and remains between the lugs while the ends 32a, 34a slide over the tongue away from slide bar lugs. Thus the operating assembly 30 is always in contact with and can control the movements of the slide bar and contact actuating mechanism whether the cover is open or closed.

To move the actuating assembly 30 laterally, the mechanism illustrated in FIGS. 4-8 is provided, operable by the switchaoperating handle 14. Handle 14 is pivotally mounted about a'pin on the cover 12 (see FIGS. 1, 8). In FIG. 8 the hub 14h and pivot pin 15 of the handle is shown in dotted lines to indicate their positions relative to other parts of the mechanism.

To guide theoverIapped bars 32 and 34 in rectilinear movement overthe unit plates 41, 42, respectively, these bars are connected transversely by spaced parallel pins 37, 3 8 which pass through a pair of parallel spaced straight slots such as 41s, 42s in each of the plates 41, 42 (see FIGS. 8 and 5). Pivotally mounted on'a pin 38 is one end of each of a pair of parallel spaced links 50'(see FIGS. 3, 4 and 5) which are rigidly connected together by a sleeve. Through the opposite ends of "links 50 passes a pivot pin 51 pivotally connecting links 50 with one end of each of a pair of spaced parallel C-shaped links 52 (only one is visible) whose opposite ends are pivotally mounted by a fixed positioned pivot pin 53 passing through said ends andinto the plates 41 and 42 near one corner of the plates.

Similar to links 50, a pair of parallel spaced links 60 are pivotally mounted at one end on a pin 37 and connected pivotally at their other ends with parallel spaced right-angle links 62 by transverse pivot pin 61. Only one link of each of the pairs of links 60, 62 is visible.

To causethe linkages 50, 52 and 60, 62 to move unitarily and at specified times and under specified-conditions, pivot pins 51, 61 are cross-connected by a channel-shapedconnector member or cross-link 65, such as illustrated in perspective in FIG. 7. Pin 61 passes through the parallel sideplates 65s of cross-link 65 at one end, and pin 51 passes through said sideplates at their other ends.

Stress is applied to the connected linkages by a coiled tension spring 70, one end of which is connected to the cross-link 65 at its center by hooking through spaced apertures 65a, 65!) (FIGS. 4, 5 and 7). The spring is connected at its opposite end to the transverse portion of a U-shaped operating yoke 72 which is pivotally mounted by bearing bosses 73 mounted coaxially in the unit plates 41, 42. The yoke stradles the crosslink 65.

To swing the yoke 72 between on and off positions as the switch-operating handle 14 is moved, in cases where the handle is offset and not coaxial with the pivotal axis of the yoke, a hole 72a is provided in the yoke to receive a pivot pin 74 fixedly mounted in a link 76 at one endwhile another pivot pin 78 fixedly secured at the opposite end of the link 76 fits into a hole in the underside of the hub 14h of the switchoperating handle 14. The link 76 lies upon the outside surface of the plate 41 between it and the cover 12. An arcuate slot 41! is formed in the unit plate 41 for passage of the pin 74. Pin 78 extends in the opposite direction from the pin 74 and an arcuate slot (not shown) is provided in the cover 12 to permit passage therethrough and engagement with the hub of the handle.

As the handle tums clockwise from the position of FIG. 8, the link 76 and pin 74 rotate the yoke 72 clockwise in FIG. 5. By referring to FIG. 5, it will be noted that the spring 70 exerts a bias or force upon the cross-link 65 toward the left of FIG. 5. This tends to hold the linkages 50, 52 and 60, 62 in the position of FIG. 5 which is the off position. By referring to FIG. 4, it willbe noted that the spring 70 in this figure exerts pressure on the cross-link 65 toward the right, thus tending to hold the linkages in the position illustrated in FIG. 4.

In order to cause the mechanism to act with a snap action and use the full force of the tension spring to operate the contact-operating mechanism and to cause contact engagement, a latching arrangement is provided including a latch bar 80 having one end upturned providing latching finger 82 while its other end is also upturned providing a pivot finger 84.

To provide pivoted support for the latch bar 80, two holes 80a and 84a are provided in the latch bar and its pivot finger, respectively. An L-shaped pivot bracket 86 bent from a narrow'st'rip of sheet metal is secured in inverted position (referring to FIGS. 4 and 5) with its end booked through hole 84a while its long leg is supported by a screw from the unit plate 45. A finger 45a bent in from sidewall 45 of the unit and enters hole 80a. To bias the latch bar 80; toward the cross-link 65 a coiled compression spring 87 is anchored at one end against the undersurface (as viewed in FIGS. 4 and 5) of the latch bar 80. The opposite end of this spring is anchored upon a supporting bracket or finger 88 which is stamped from a strip of sheet metal in L-shape with its short leg supported by the same screw that supports the pivot bracket 86 and with its long leg extending into the mechanism as illustrated in FIGS. 4 and 5. Thus when the parts are in the position of the FIG. 5, the spring 87 biases the latch bar 80 in a counterclockwise direction against cross-link 65 with the finger 82 of the latch bar hooked around the end of the cross-link. The spring 87 tends to maintain pivotal engagement of the opposite end of the latch bar with the pivot finger 45 a.

Thus as the yoke is moved clockwise in FIG. 5, it will eventually come to a point where the stress of the spring will exercise a component of force horizontally sufficient to urge the cross-link 65 to the right and this component will continue and increase in amount as the yoke is movedfurther clockwise. However, this movement is restrained by the engagement of the finger 82 with the cross-link 65. To release this engagement, coaxial short round trip lugs 89 are mounted on the inside surface of the arms of the yoke (one on each arm) in position to move in parallel arcuate paths and engage the symmetrical lateral wings 80w which project from each side of the latch bar 80 and lie in said paths. When the yoke has been rotated about approximately or a substantial part of its full travel from off" position of FIG. 5 to onfposition of FIG. 4, but in any event after the bias of the linkage has changed from the position of FIG. 5 to urge it into the FIG. 4 position, the lugs 89 will engage the latch bar and disengage it from the cross-link 65. As soon as the latch finger 82 disengages from the cross-link 80, the parts will snap into FIG. 4 position. In FIG. 4 position the horizontal component of spring bias is exerted on the cross-link to the right and predominates over the vertical upward component, so that the mechanism is held in the on" position.

In order to return to the FIG. 5 position, the yoke 72 is moved by the operating handle 14 in counterclockwise direction during which the component of spring force changes. The horizontal component weakens as the vertical upward component increases until the friction of the switch contacts is overcome and frees the actuating assembly 30 for movement (up, from FIG. 4 position to FIG. 5 position). This permits the pivot pins 37, 38 (which support the actuating assembly 30) to move up under the spring pressure and the linkage to collapse into the position of FIG. 5.

To insure positive separation of the contacts in case they should be stuck or welded, a cam surface 720 is formed on the yoke to engage the pivot pin 61 as the yoke moves, counterclockwise, from the on to the off position. This cam action exerts a positive force tending to move the pin 61 clockwise about the pivot 63 of the link 62, which will carry the link 60 upward. The cross-link 65 will transmit the same action and impart the same effect to the pin 51 and pull the link 50 up. This upward pull of the links 50 and 60 on the actuating assembly 30 is transmitted to the switch contacts by the previously described contact-operating mechanism to ensure contact separation.

In order to prevent movement from the off" position into the on position while the cover is open, a spring-biased latch member 90 stamped from sheet metal into right-angular shape with a latch nose 90a on one end of one arm of that member and a fingerlike extension 90f is formed on the end of the other arm and is bent at a right angle to the plane of the member. The latch 90 is pivotally mounted on the surface of the unit plate 41 by a pin 91. A coiled compression spring 92 presses against the finger-arm biasing the nose 90a toward the handle connected link 76 which as a notch 76a cut in its edge to receive the latch nose 90a when the handle is moved toward on" position while the cover is open. To release the latch 90 when the cover closes, a V-shaped cam slot c (FIGS. 1 and 8) is cut into the top edge of the sidewall of the box 10 in position to engage the finger 90f of the latch 90 and to rotate the latch counterclockwise (FIG. 8) i.e., away from the handle link 76. Thus the handle is free to move to on position when the cover is closed. The handle is at all times free to move the switch to off" position when the cover is open or closed since the latch 90 only operates to prevent movement of the handle in one direction.

In order to lock the cover when the switch mechanism is moved to on" position, a latch bar 95 is slidably mounted against and parallel to the surface of the unit plate 43 by spaced pins 96, 97 (FIGS. 3 and 8) which pass through aligned spaced slots 95s in the sliding latch bar 95 and are fixedly mounted in the plate 43. The latch 95 has a beveled end positioned to engage the edge of a transverse bar 126 as the cover closes and to slide longitudinally away from the bar until the cover is closed. Then the spring bias actuates the latch to slide it under the bar 126 prevents opening of the cover.

In order to bias the latch bar 95 toward latching position, when the mechanism is in on position and to retract the latch bar 95 when the switch mechanism is moved to off, a pivotally mounted spring release lever 98 biased by spring 92 is mounted on a pivot pin 99 which is fixedly mounted on the unit plate 41 near the latch 95. One end 98a of the release lever 98 extends through an aperture in the latch 95 (FIGS. 3 and 8) while the other end extends oppositely into the path of the end of the handle-connected link 76 so that when that link moves into off position it engages the release lever 98 pivoting it clockwise (FIG. 8) which in turn slides the latch bar 95 from under the crossbar 126 thus freeing the cover for'opening movement.

Should the latch 90 be momentarily manually held out of the path of the handle-connected link 76 and the switch mechanism be then moved to on position while the cover is open, the sliding latch bar 95 will be biased by the lever 98 into latching position. The cover may then be closed during which movement the sliding latch bar 95 will be slid against its bias away from the crossbar 126 by the cam action of that bar on the end of the sliding latch until the cover is fully closed. Then the end of the sliding latch will move by its spring bias to a position underneath the crossbar and lock the cover closed.

If the switch-is in closed position while the cover is open, the handle may be operated to move the switch to off position, due to the connection between the actuating mechanism and the contact-operating mechanism through the assembly 30 as hereinbefore described.

From the foregoing, the operation of the invention will be apparent.

All of the parts of the operating mechanism may readily be made from stamped sheet metal, except the pivot pins, bail and handle which may readily be made from rods and, in the case of the handle, by casting or molding. Although the handle is shown as being located with its pivot offset from the pivotal axis of the yoke, the handle may be mounted with its axis coinciding with the axis of the yoke.

Many modifications within the scope of the invention will occur to those skilled in the art. Therefore the invention is not limited to the precise form and configuration of parts as illustrated and described.

What I claim is:

I. In combination, an enclosure having a hinged cover with a hinge axis, an electric switch within said enclosure, said electric switch having fixed and movable contact means snap action means including a manually operable handle on said cover, contact-operatng means mounted in said enclosure, means connecting said snap action means with said contactoperating means when said cover is open and when said cover is closed enabling operation of said contact operating means into contact-disengaging position in both positions of the cover, said connecting means including a member slidable in a path parallel to said hinge axis and a slidable assembly having an arcuate portion movable with said cover having a radius of curvature whose center is located in the cover-hinge axis and being laterally movable with respect to said slidable member.

2. The combination as claimed in claim 1 having contactengagement-prevention means normally preventing movement of said contact means into engagement while said cover is open.

3. The combination as claimed in claim 2 having latching means to prevent opening of said cover while said contact means are engaged.

4. The combination as claimed in claim 3 having means moving with said cover and operated by movement of said snap action means into contact disengaging position to disable said cover latching means.

5. The combination as claimed in claim 2 wherein said snap action means disables said contact-engagement-prevention means on movement to contact disengaged position.

6. The combination as claimed in claim 1 having contactengagement-prevention means normally preventing movement of said contact means into engagement while said cover is open, said contact-engagement-prevention means being positioned for manual engagement to disable the same when the cover is open.

7. The combination as claimed in claim 1 having means to guide the movable contact means linearly toward and from the back of said enclosure.

8. The combination as claimed in claim 7 wherein said connecting means includes means pivotally mounted from walls of said enclosure to transmit snap action to said contact means.

9. The combination as claimed in claim I, further including a slidable arcuate extension on said arcuate portion to maintain engagement with said slidable member as the cover becomes fully open.

10. In combination, an enclosure having a hinged cover and side and back walls, an electric switch having fixed and movable contact means within said enclosure, means to guide said movable contact means rectilinearly toward and from the back of said enclosure, snap action means including a manually operable handle mounted on said cove, means moved transversely of said enclosure as the snap action means operates, contact-operating means mounted in said enclosure and connecting said movable contact means and said transversely movable means for operating said movable contact means to cause contact engagement and disengagement, means connecting said snap action means with said contact-operating means when said cover is open and also when said cover is closed, said connecting means including means pivotally mounted from said sidewalls and a bellcrank lever to transmit the transverse snap action to said movable contact means for operation of said contact operating means into contact disengaging position in both positions of the cover 11. In combination, an enclosure having a hinged cover, an electric switch having fixed and movable contact means within said enclosure, snap action means including a manually operable handle mounted on said cover, said snap action means also including actuated means movable transversely of said enclosure, contact-operating means in said enclosure to cause contact engagement and disengagement, said contact operating means including transversely slidable means mounted on said enclosure and engaged by said actuated means in both coveropen and cover-closed positions enabling contact operation in both positions of the cover, said contact-operating means also including pivoted means supported from the enclosure and enga'ged with said enclosure-mounted transversely slidable means for translating the transverse movement to movement in a plane lengthwise of the enclosure.

12. The combination as claimed in claim 11 wherein said actuated means includes an arcuate portion whose center coincides with the pivotal axis of said hinged cover.

13. In an electric switch having relatively movable contact means, means connected to said contact means to cause engagement and disengagement of said contact means with a snap action comprising a pivoted yoke, means to manually operate said yoke, a linkage including a pair of links pivotally connected at one end and a second pair of links pivotally connected at one end, two spaced fixed pivots mounting one end of a first link of each pair respectively, a cross connection between the connected ends of the links of each pair, means guiding the opposite ends of the second links of each pair for parallel rectilinear movement, spring means connecting said yoke and said cross connection to transmit the motion of the yoke to said linkage, a pivoted latch holding said cross connection and linkage in one position while said yoke is moving from one positionto another, means on said yoke disengaging the latch hold o'f said cross connection after predetermined movement of the yoke to free said linkage for snap action to another position to operate said contract means.

14. In an electric switch having relatively movable contact means, means to cause engagement and disengagement of said contact means with a snap action comprising a manually actuatable actuating member, linkage means comprising links each movable from one position to another causing operation of said contact means, spring means applying stress tending to move said linkage .means as said actuating member moves from one position toward an other, latching means holding said linkage means as said actuating member moves from one position toward another, means moved by said actuating member to release said latching means when said actuating member has moved a predetermined distance freeing said linkage means for movement with a snap action to said other position.

15. The combination as claimed in claim 14 in which said linkage means comprises two linkages each having pivotally connected links, a cross connection between the two linkages causing them to have joint similar actions, said latching means holding both the cross-connected linkages as said actuating member moves from one position toward another.

16. The combination as claimed in claim 15 having means guiding the ends of corresponding links of the two linkages for parallel movement.

17. The combination as claimed in claim 14 having means moved by said'actuating member to positively actuate said linkage means when said linkage means is to move from said other position to said one position, to ensure contact separation in case of sticking or welding of said contact means.

18. The combination as claimed in claim 15 having means moved by said actuating member positively acting upon said pivotally connected links to positively move said linkages when they are to move from said other position to said one position, to ensure contact separation in case of sticking or welding of said contact means.

19. The combination as claimed in claim 18 having means guiding the ends of corresponding links of the two linkages for parallel movement.

20. in combination, an enclosure having a hinged cover with a hinge axis, an electric switch having fixed and movable contact means within said enclosure, actuating means including a manually operable handle mounted on said cover, contactoperating means to cause contact engagement and disengagement mounted in said enclosure, means connecting said actuating means with said contact-operating means when said cover is open and also when it is closed enabling operating of said contact-operating means into contact-disengaging position in both positions of the cover, said connecting means including a member slidable in a path parallel to said hinge axis, and an arcuate member movable with said cover, having a radius of curvature whose center is located in the cover-hinge axis and being laterally movable with respect to said slidable member.

21. The combination as claimed in claim 20 having contactengagement-prevention means normally preventing movement of said contact means into engagement while said cover is openv 22. The combination as claimed in claim 21 having latching means to prevent opening of said cover while said contact means are enga ed.

23. The com ination as claimed in claim 22 having means moving with said cover and operated by movement of said actuating means into contact-disengaging position to disable said cover latching means.

24. The combination as claimed in claim 21 wherein said actuating means disables said contact-engagement-prevention means on movement to contact disengaged position.

25. The combination as claimed in claim 20 having contactengagement-prevention means. normally preventing movement of said contact means into engagement while said cover is open said contact-engagement-prevention means being positioned for manual engagement to disable the same when the cover is open.

26. The combination as' claimed in claim 20 wherein the means connecting said actuating means with said contactoperating means comprises an arcuate portion movable with the cover, which maintains engagement with said operating means as the cover opens.

27. The combination as claimed in claim 20 having means to guide the movable contact means linearly toward and from the back of said enclosure, and saidactuating means includes means moved transversely of said enclosure as said actuating means operates, and means connecting said movable contact means and said transversely movable means for operating said movable contact means. 

1. In combination, an enclosure having a hinged cover with a hinge axis, an electric switch within said enclosure, said electric switch having fixed and movable contact means snap action means including a manually operable handle on said cover, contact-operatng means mounted in said enclosure, means connecting said snap action means with said contact-operating means when said cover is open and when said cover is closed enabling operation of said contact operating means into contactdisengaging position in both positions of the cover, said connecting means including a member slidable in a path parallel to said hinge axis and a slidable assembly having an arcuate portion movable with said cover having a radius of curvature whose center is located in the cover-hinge axis and being laterally movable with respect to said slidable member.
 2. The combination as claimed in claim 1 having contact-engagement-prevention means normally preventing movement of said contact means into engagement while said cover is open.
 3. The combination as claimed in claim 2 having latching means to prevent opening of said cover while said contact means are engaged.
 4. The combination as claimed in claim 3 having means moving with said cover and operated by movement of said snap action means into contact disengaging position to disable said cover latching means.
 5. The combination as claimed in claim 2 wherein said snap action means disables said contact-engagement-prevention means on movement to contact disengaged position.
 6. The combination as claimed in claim 1 having contact-engagement-prevention means normally preventing movement of said contact means into engagement while said cover is open, said contact-engagement-preVention means being positioned for manual engagement to disable the same when the cover is open.
 7. The combination as claimed in claim 1 having means to guide the movable contact means linearly toward and from the back of said enclosure.
 8. The combination as claimed in claim 7 wherein said connecting means includes means pivotally mounted from walls of said enclosure to transmit snap action to said contact means.
 9. The combination as claimed in claim 1, further including a slidable arcuate extension on said arcuate portion to maintain engagement with said slidable member as the cover becomes fully open.
 10. In combination, an enclosure having a hinged cover and side and back walls, an electric switch having fixed and movable contact means within said enclosure, means to guide said movable contact means rectilinearly toward and from the back of said enclosure, snap action means including a manually operable handle mounted on said cove, means moved transversely of said enclosure as the snap action means operates, contact-operating means mounted in said enclosure and connecting said movable contact means and said transversely movable means for operating said movable contact means to cause contact engagement and disengagement, means connecting said snap action means with said contact-operating means when said cover is open and also when said cover is closed, said connecting means including means pivotally mounted from said sidewalls and a bellcrank lever to transmit the transverse snap action to said movable contact means for operation of said contact operating means into contact disengaging position in both positions of the cover
 11. In combination, an enclosure having a hinged cover, an electric switch having fixed and movable contact means within said enclosure, snap action means including a manually operable handle mounted on said cover, said snap action means also including actuated means movable transversely of said enclosure, contact-operating means in said enclosure to cause contact engagement and disengagement, said contact operating means including transversely slidable means mounted on said enclosure and engaged by said actuated means in both cover-open and cover-closed positions enabling contact operation in both positions of the cover, said contact-operating means also including pivoted means supported from the enclosure and engaged with said enclosure-mounted transversely slidable means for translating the transverse movement to movement in a plane lengthwise of the enclosure.
 12. The combination as claimed in claim 11 wherein said actuated means includes an arcuate portion whose center coincides with the pivotal axis of said hinged cover.
 13. In an electric switch having relatively movable contact means, means connected to said contact means to cause engagement and disengagement of said contact means with a snap action comprising a pivoted yoke, means to manually operate said yoke, a linkage including a pair of links pivotally connected at one end and a second pair of links pivotally connected at one end, two spaced fixed pivots mounting one end of a first link of each pair respectively, a cross connection between the connected ends of the links of each pair, means guiding the opposite ends of the second links of each pair for parallel rectilinear movement, spring means connecting said yoke and said cross connection to transmit the motion of the yoke to said linkage, a pivoted latch holding said cross connection and linkage in one position while said yoke is moving from one position to another, means on said yoke disengaging the latch hold of said cross connection after predetermined movement of the yoke to free said linkage for snap action to another position to operate said contract means.
 14. In an electric switch having relatively movable contact means, means to cause engagement and disengagement of said contact means with a snap action comprising a manually actuatable actuating member, linkage means comprising lInks each movable from one position to another causing operation of said contact means, spring means applying stress tending to move said linkage means as said actuating member moves from one position toward an other, latching means holding said linkage means as said actuating member moves from one position toward another, means moved by said actuating member to release said latching means when said actuating member has moved a predetermined distance freeing said linkage means for movement with a snap action to said other position.
 15. The combination as claimed in claim 14 in which said linkage means comprises two linkages each having pivotally connected links, a cross connection between the two linkages causing them to have joint similar actions, said latching means holding both the cross-connected linkages as said actuating member moves from one position toward another.
 16. The combination as claimed in claim 15 having means guiding the ends of corresponding links of the two linkages for parallel movement.
 17. The combination as claimed in claim 14 having means moved by said actuating member to positively actuate said linkage means when said linkage means is to move from said other position to said one position, to ensure contact separation in case of sticking or welding of said contact means.
 18. The combination as claimed in claim 15 having means moved by said actuating member positively acting upon said pivotally connected links to positively move said linkages when they are to move from said other position to said one position, to ensure contact separation in case of sticking or welding of said contact means.
 19. The combination as claimed in claim 18 having means guiding the ends of corresponding links of the two linkages for parallel movement.
 20. In combination, an enclosure having a hinged cover with a hinge axis, an electric switch having fixed and movable contact means within said enclosure, actuating means including a manually operable handle mounted on said cover, contact-operating means to cause contact engagement and disengagement mounted in said enclosure, means connecting said actuating means with said contact-operating means when said cover is open and also when it is closed enabling operating of said contact-operating means into contact-disengaging position in both positions of the cover, said connecting means including a member slidable in a path parallel to said hinge axis, and an arcuate member movable with said cover, having a radius of curvature whose center is located in the cover-hinge axis and being laterally movable with respect to said slidable member.
 21. The combination as claimed in claim 20 having contact-engagement-prevention means normally preventing movement of said contact means into engagement while said cover is open.
 22. The combination as claimed in claim 21 having latching means to prevent opening of said cover while said contact means are engaged.
 23. The combination as claimed in claim 22 having means moving with said cover and operated by movement of said actuating means into contact-disengaging position to disable said cover latching means.
 24. The combination as claimed in claim 21 wherein said actuating means disables said contact-engagement-prevention means on movement to contact disengaged position.
 25. The combination as claimed in claim 20 having contact-engagement-prevention means normally preventing movement of said contact means into engagement while said cover is open said contact-engagement-prevention means being positioned for manual engagement to disable the same when the cover is open.
 26. The combination as claimed in claim 20 wherein the means connecting said actuating means with said contact-operating means comprises an arcuate portion movable with the cover, which maintains engagement with said operating means as the cover opens.
 27. The combination as claimed in claim 20 having means to guide the movable contact means linearly toward and from the back of said enclOsure, and said actuating means includes means moved transversely of said enclosure as said actuating means operates, and means connecting said movable contact means and said transversely movable means for operating said movable contact means. 